Plotter displays: CHECKSUM ERROR message.
Plotter displays: CHECKSUM ERROR message.
A. Checksum is a method of checking the integrity a block of data by
applying a summation algorithm to each byte in the block of data. The
resulting checksum value is appended as the last byte in the block.
When data is sent from the host, the checksum value sent from the host
is compared with a checksum value generated by the plotter. If the
checksum values match, it is assumed that the transmitted data is the
same as the received data. If the characters don't match, it is
assumed the data is bad.
B. To eliminate checksum errors, perform the following:
1. Check if the application software package is using checksumming.
Refer to the application software users guide or Appendix B of
the 104x User's Guide for a list of common software application
settings.
a. If it is not known whether the software application is
using checksumming or not, and the CAD software User's
Guide does not provide that information, then first try
choosing enabled (enabled = Yes). If enabled results in a
Checksum Error, then try disabled (disabled = NO).
2. Check the Set-up menu on the plotter. To do this, perform the
following:
a. Turn on the plotter power.
b. Load and size the media.
c. Take the plotter off-line by pressing the AUTO/MANUAL key.
d. Press the SETUP key.
e. The plotter will display:
Setup number:
Press NEXT for MENU
f. Press the key marked 7 (numeric 7) on the plotter keypad.
g. Press the ENTER key.
h. The plotter will display:
Host Setup Number:
Press NEXT for MENU:
i. Press the key marked 4 (numeric 4).
j. Press the ENTER key.
k. The plotter will display:
Term Muting Y/N ?
Cksum Enable Y/N ?
l. Enable checksumming by pressing the ENTER key to answer
yes. Press the CLEAR/NO key for no checksumming.
m. After selecting the appropriate setting for checksumming,
press the SAVE/TEST key. The plotter will display:
User Number:
Press 1, 2, 3, or 4 followed by pressing the ENTER key to
save the new values to that user number and exit the menu.
C. Other factors that can cause a checksum error include anything between
the computer and plotter that might cause a communication problem. To
help isolate this kind of communication problem, note the following:
1. Eliminate any spoolers, buffers, networks, switch boxes etc., and
direct connect the plotter to the host computer.
a. If using an IBM PC or compatible or a Sun workstation with
an RS232 port:
i. Try another serial cable. A bad serial cable can
cause the data to be dropped on its way from the
computer to the plotter. The plotter uses a straight-
through, 25-pin female to 25-pin male serial cable
(CalComp part number 11772-0250, 25 foot serial
cable) This is not a proprietary cable. It is
commercially available, sometimes called a MODEM
cable or a serial extension cable. Note: A NULL-MODEM
cable is the incorrect cable.
ii. The total cable length should not exceed 50 feet.
For testing purposes a shorter cable can decrease the
error factor.
iii. If the computer has a 9-pin connector for the COM
port (i.e. COM1 or COM2), a commercially available 9
to 25 pin adapter is acceptable to perform the
conversion.
iv. Connect the cable to the port on the back of the
plotter labeled: P0903 - To DTE Host.
b. If using a Macintosh computer:
i. Try a different communications cable. The plotter
uses an 8-pin mini-din Macintosh to 25-pin serial
cable (CalComp part number 16623-0029, 12 ft.
cable).
c. Send a different plot file. The plot file being sent may
be corrupt.
d. Try plotting from another computer. The port on the
computer may be defective.